Back in early '08 I heard noise I didn't like from the rear, opened the 8 3/8 chrysler diff cover to find some heavily pitted spider gears, a caked magnet, and pitted axleshafts where they ride on the outer bearings.
Got a few quotes from people who recommended I just get a junkyard axle. All quotes were all in the 1600 to 1800$ range with a big asterix depending on if R&P could be reused.
I did the junkyard scramble and found a 9.25 chrysler with the same 3.55:1 ratio. There was not a lot of fuzz on magnet. 500$.
I installed it and it was louder than the 8 3/8.
But, I'd needed a conversion U joint to fit the larger 9.25 yoke.
When I opened up the old U joint, all the roller bearings were flattened and kinked diagonally in the caps!
Likely the source of the noise which had me condemn the 8 3/8.
I took the vehicle to a driveline shop. They found the junkyard axle housing was bent, straightened it, painted it, new bearings, yelled at me for using loc tite red on U bolts. 800+ dollars.
60k miles later I try to tell myself I did not screw up, that I'm better off with a slightly heavier duty axle... its water and money long long under the bridge.
It's still quiet.
Put some Schaeffers 293 75w-90 in there about 12k mostly highway miles ago.